I want to go away but I don't want my family to find out and be upset?

Believe me life gets much better. I don't know anyone who didn't have despairing thoughts at nineteen! I'm in my 60s now and every decade has just gotten better. If I'd given way to despondency in my teens I'd have missed so much. Have you given some thought to going away in the more productive sense? Drop out of school for a while and work! Get a job where you have to work hard--physically--to the point of being really tired after the day is done. Live on your own and be responsible for all your needs. Move to a city where no one knows you and go by your middle name. I did that for a while before completing my education and it meant a lot to me. It's sort of like killing off your old self without the hle of actually dying!